1. Field of the Invention
This invention relates generally to navigation. In particular, an exemplary aspect of this invention relates to coordinating Global Positioning System (GPS), or other system, provided coordinates with a physical map. Another exemplary aspect of this invention relates to a device for use in conjunction with a GPS receiver that allows one to pinpoint an exact location on a map.
2. Description of Related Art
Various devices have been developed since the 1800s to aid in maritime navigation by adjusting sliding devices along scales made parallel to the edges of the maritime charts to determine intermediate latitudes and longitudes. From this, a location coordinate on the map could be determined. Most of these devices assume a flat surface such as a table, or some other near horizontal surface upon which to place the chart and device. Some devices have also been developed for aeronautical navigation and some have anticipated land navigation but assume use in a land vehicle where support would be available.
The GPS is a constellation of satellites which orbit the Earth. This system was developed by the U.S. military, however became publicly available to assist the public with global navigation. With advent of the GPS satellite system and the current state of GPS receivers, an ambulatory person can see their location on a map displayed by the GPS receiver. GPS receivers provide accurate location information but their display size compromise the amount of topographic information that can be displayed in context, to a user.
A user can connect the GPS receiver to a portable computer with a large screen which would then display the necessary topographic detail in context with a large enough map area for navigation and planning purposes, but for many ambulatory persons this is not a practical solution because of weight, battery life, cost and operational difficulties. It is still useful for ambulatory persons to use a handheld map and transform the GPS provided map coordinates onto the map for their en-route navigation and planning.
A simple device exists to aid in the transformation of the GPS provided coordinates by providing small orthogonal scales on a transparent base that are held against the map at the appropriate intersection of two coordinate lines. The device is then moved horizontally and vertically on the map parallel to the map coordinate lines, to arrive at the actual position on the map between lines that the GPS provided coordinates represent. This is a simple method but it is prone to interpretation and operator error in field conditions utilizing hand-held maps.